Relationships between social intelligence, empathy, and three types of aggressive behavior were studied. Peer-estimation techniques were used to measure all major variables. Altogether, 526 Finnish schoolchildren from three age groups (10, 12, and 14 years old) participated in the study. As was hypothesized, indirect aggression correlated positively and significantly with social intelligence in every age group studied. Physical and verbal forms of aggression had almost zero correlation to social intelligence. Empathy correlated negatively and significantly with every type of aggression except indirect aggression in 12-year-old children. The major findings are in line with the developmental theory by Björkqvist et al. [1992. Aggr Behav 18:117–127] suggesting that indirect aggression requires more social intelligence than direct forms of aggression. Aggr. Behav. 25:81–89, 1999. © 1999 Wiley-Liss, Inc.